The present invention relates to a recording apparatus equipped with a carriage carrying a recording head in a primary scanning direction to perform recording on a recording medium. The invention also relates to a liquid ejecting apparatus equipped with a carriage carrying a liquid ejecting head in a primary scanning direction to eject liquid toward a target medium.
The liquid ejecting apparatus refers to a recording apparatus such as a printer, copier and a facsimile machine that uses an ink jet recording head and ejects ink from the recording head to perform recording on a recording medium, as well as an apparatus that ejects suitable liquid onto a target medium from a liquid ejecting head in order to land the liquid onto the target medium.
The liquid ejecting head may be a color material ejecting head used for manufacturing a color filter for a liquid crystal display, an electrode material (conductive paste) ejecting head used for producing of an electrode for an organic EL display or a field emission display, a bioorganic matter ejecting head used for manufacturing a biochip, and a sample ejecting head serving as a micropipette.
An ink jet printer as an example of a recording apparatus or a liquid ejecting apparatus will be described. An ink jet printer comprises a carriage for carrying a recording head adapted to eject ink onto printing paper. The carriage is designed to be guided by a guide shaft extending in a primary scanning direction while being engaged with a portion of an endless belt, so that the carriage is reciprocated in the primary scanning direction while being pulled by the endless belt.
The carriage is classified into two types: a carriage that mounts an ink cartridge, so-called an on-carriage type and a carriage that does not mount an ink cartridge, so-called an off-carriage type. For an off-carriage type ink jet printer where an ink cartridge is not mounted on a carriage, an ink cartridge provided separately from the carriage and an ink jet recording head are interconnected with a flexible member such as an ink tube in which an ink channel is formed.
In this example, the flexible member has a self-restoration property to return to a straight shape. The restoring force caused by the self-restoration property acts on the carriage thus causing an adverse effect on the carriage operation thereby degrading the ink landing accuracy and recording quality.
In order to solve such a problem, Japanese Patent Publication No. 2002-321351A discloses an ink jet recording apparatus wherein an ink tube and a flexible flat cable are respectively arranged on one side and on the other side of a carriage in a primary scanning direction so that the restoring force caused by the self-restoration property of each of the tube and the cable to cancel each other thereby obtaining a balance of force applied to the carriage.
With this configuration, however, the size of the apparatus in the primary scanning direction is enlarged because it is necessary to provide spaces for the tube and the cable in both sides of the carriage. Further, it is necessary to adjust the restoring forces of both elements to an optimum level, which reduces the freedom of design. In particular, an ink tube or a flexible flat cable has the curvature of a curved part to be changed due to the travel of the carriage in the primary scanning direction. That is, the restoring force also changes so that consideration of a balance of the restoring forces of these elements to appropriately cancel each other is likely to be difficult.
In addition, in a case where the carriage is pulled by an endless belt, the direction of the force applied to the carriage differs between going stroke and returning stroke in the reciprocation of the carriage. This presents the problem of “swing” phenomenon of the carriage (described later in detail) that could result in degraded ink landing accuracy and recording quality.